Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3734_Библиотеки_им_академика_М_И_Перельмана
.pdf
Management of Chronic Dissection of the Descending Thoracic and Thoracoabdominal…
https://t.me/med1917
429
guide permissive hypothermia. A Foley catheter facilitates monitoring kidney function and controlling uid balance. Patients are intubated with a double-lumen endobronchial tube for single-lung ventilation during the procedure. A CSFD catheter is
inserted by the anesthesia team at the L3–4, L4–5, or L5–S1 level. The patient is
administered prophylactic antibiotics—vancomycin and cefepime—1hour before
the initial incision. In patients with prior elephant trunk repair, ultrasonography is
used to locate the graft that is hanging within the proximal portion of the descending
thoracic aorta.
Positioning
The patient is commonly arranged in a right lateral decubitus position, with the
upper body at a 60° angle in relation to the operating table. The hips are then angled
30° to the horizontal (Fig.3). The lower limbs are positioned to allow rapid access
to the femoral arteries if cannulation becomes necessary. A beanbag is inated to
maintain this position.
shoulders
60°
hips
30°
Fig. 3 Positioning of the patient, incision, and exposure of thoracoabdominal aorta to prepare for
repair of chronic aortic dissection. Used with permission of Baylor College of Medicine
430
https://t.me/med1917
C. Köksoy et al.
Exposure
Our surgical approach to open repair of DTA and TAAA has been described previously [32]. Briey, for isolated DTA repair, the segment to be replaced is approached
through a posterolateral thoracotomy through the fth or sixth intercostal space,
depending on the extent of repair. For Crawford extent I and II TAAAs, a sigmoidshaped skin incision is made from behind the left scapula, along the seventh rib,
across the costal margin, and toward the left periumbilical region. The chest is
entered through the sixth intercostal space. For extent III TAAA repairs, the seventh
or eighth intercostal space is entered; for extent IV TAAA repairs, a straight oblique
incision is made through the ninth or tenth intercostal space. Left medial visceral
rotation and circumferential division of the diaphragm enable exposure of the entire
thoracoabdominal aorta. Using table-mounted self-retaining retractors maintains
stable exposure throughout the procedure. The entire thoracoabdominal aorta is
exposed by medial visceral rotation and circumferential division of the diaphragm.
Possible clamp sites are dissected. In patients with chronic DeBakey type I aortic
dissection, prior adhesions related to previous proximal aortic surgery necessitate
more dissection, which makes preparing the proximal clamp site more challenging;
however, if the patient underwent prior aortic arch replacement with an elephant
trunk extension, the trunk is used as the proximal clamp site, which lessens preparation. In cases with no appropriate proximal site (e.g., contained rupture, an extremely
large aneurysm, extension into the distal transverse arch), hypothermic circulatory
arrest is used.
Left Heart Bypass
Left heart bypass is used routinely in Crawford extent I and II repairs and selectively in other distal aortic repairs. After heparin (1mg/kg) is administered, a cannula is placed in the left atrium via left inferior pulmonary venotomy, held with a
purse-string suture, and connected to the drainage line of the LHB circuit. Another
cannula is placed in the distal descending thoracic aorta and connected to the circuit’s inow line. After LHB ow is initiated, the proximal aortic clamp is placed
just distal or proximal to the left subclavian artery. Performing the proximal anastomosis during repair of DTA and TAAA is technically challenging; establishing a
proximal aortic cuff that is sufciently long and suitable for suturing is critical.
Most commonly, this anastomosis is made immediately beyond the clamp placed
distal to the left subclavian artery. However, in cases involving substantial dilatation
of the distal arch (which is not uncommon in patients with DeBakey type I aortic
dissection), the clamp is placed across the transverse aortic arch proximal to the left
subclavian artery, and a bulldog clamp is used to occlude the left subclavian artery
(Fig.4). Once proximal control is established, a second aortic clamp is placed across
the mid-descending thoracic aorta, and LHB ows are increased.
Management of Chronic Dissection of the Descending Thoracic and Thoracoabdominal…
https://t.me/med1917
vagus nerve
3cm
Recurrent
laryngeal nerve
Fig. 4 Initiation of left heart bypass, placement of aortic clamps, and opening of the proximal
descending thoracic aorta. (Inset) In repairs involving chronic dissection, the dividing septum is
removed. Used with permission of Baylor College of Medicine
431
Proximal Anastomosis
The isolated segment of the proximal descending thoracic aorta is longitudinally
opened, and the aorta is completely divided at the level of the proximal anastomosis.
All shed blood is collected and returned to the patient through a cell saver system.
Then, the thick dissecting membrane between the true and false lumens is excised
(Fig.4). Meanwhile, patent intercostal arteries at this level are oversewn with 2–0
silk sutures. For the proximal anastomosis, the aorta is transected, which allows
full-thickness suturing through the aortic wall without risk of injuring the esophagus, pulmonary artery, or recurrent laryngeal nerve and allows absolute conrmation of all channels in the dissected aorta (Fig.5).
To perform the proximal anastomosis, we typically use continuous 3–0 polypropylene suture; however, in patients with heritable disorders like MFS, we prefer ner suture
material, either 4–0 or 5–0. The graft material of choice for aortic surgery is Dacron
impregnated with either collagen or gelatin; the graft is soaked tableside in rifampin.
For distal aortic repair, usually, a 24-, 26-, or 28-mm graft is used. The rst stitch is
placed at the posterolateral corner of the aorta and tied. Because it is difcult to rotate
432
https://t.me/med1917
Fig. 5 An aortic replacement graft is sized to length to prepare for the proximal anastomosis. In
this segment, the spinal arteries are ligated. (Inset) For repairs limited to the descending thoracic
aorta (DTA), left heart bypass is typically not used. Beginning with the difcult-to-rotate posterior
portion, the proximal anastomosis is rst sutured transluminally; DTA repair is typically performed without using a distal aortic clamp (i.e., using an open distal anastomosis approach)
C. Köksoy et al.
the aorta, we perform the posterior half of the suturing transluminally (Fig.5). The
suture is passed through all layers, with particular care taken to include the intima. The
posterior part of the anastomosis is accomplished by running the suture medially (away
from the surgeon) (Fig.6). After the primary suture line is completed and the suture
ends are tied, the graft is gently lifted up and the posterior portion of the anastomosis is
carefully examined. Pledgeted mattress sutures are applied to areas with widely separated sutures, overlapping sutures, or tears in the aorta. In patients with notable dilation
or residual dissection of the aortic arch, a reversed elephant trunk approach may be
undertaken to facilitate subsequent proximal aortic repair; an extended (approximately
8-cm) portion of the replacement graft is invaginated to create the reversed elephant
trunk, and the folded edge is used to create the proximal anastomosis.
Sequential Graft Clamping
Once the proximal anastomosis is complete, LHB is tapered and then discontinued.
The aortic cross-clamp is removed and placed further distal on the graft (Fig.7).
Moving the clamp is especially crucial if it was originally placed proximal to the left
Management of Chronic Dissection of the Descending Thoracic and Thoracoabdominal…
https://t.me/med1917
Fig. 6 Construction of the proximal anastomosis. Used with permission of Baylor College of
Medicine
433
Fig. 7 Extension of the aortic incision after the aortic cross-clamp is moved down onto the graft.
Used with permission of Baylor College of Medicine
434
https://t.me/med1917
subclavian artery, because moving it distally re-establishes ow to the subclavian
and vertebral arteries. The distal cannula can be removed, and the distal cross-clamp
released. With scissors or electrocautery, the aorta is opened longitudinally; the
length of the incision depends on the extent of repair and may extend to the bifurcation of the iliac arteries. The aortic wall is prepared by excising the dissecting septum and manually removing any thrombus; this allows exposure of all intercostal,
visceral, and lumbar branches. As possible throughout repair, the clamp is repositioned to aid perfusion and thereby reduce ischemic conditions.
C. Köksoy et al.
Reimplantation ofSpinal Arteries
Any rapidly bleeding spinal arteries are ligated. If there is good backow, the inferior mesenteric artery is ligated with 2–0 silk suture. Of the remaining spinal arteries, a pair is selected for reimplantation into the aortic graft. These arteries should
be between T7 and L2, close to each another, and large in caliber, and they should
have no back-bleeding. Two techniques can be used to reattach the spinal arteries:
an island patch or a small-diameter (8-mm) interposition graft. If the patient’s
anatomy is favorable, we prefer to implant the arteries as a patch, while incorporating a minimal amount of native aortic tissue. To reattach the arteries, a hole is
cut into the Dacron graft, and the graft and island patch are anastomosed side-toside with 3–0 polypropylene suture (Fig.8). In areas where the native aortic tissue
is fragile, a 3–0 or 4–0 pledgeted mattress suture can be used as reinforcement.
After the patch reimplantation of the intercostal arteries is completed, whenever
possible, the proximal aortic cross-clamp is moved down the aortic graft to a position immediately distal to the intercostal patch to allow reperfusion of the reimplanted spinal arteries. If repair is limited to the descending thoracic aorta, the
distal anastomosis is performed as an open procedure (Fig.5); the dissecting membrane between the true and false lumen is fenestrated to ensure that both lumens
remain perfused.
Management ofVisceral Arteries
Care must be taken to identify the renal and visceral arteries. In particular, the left
renal artery is often displaced in patients with chronic dissection. During reimplantation of the spinal arteries, if any of the renal artery ostia are accessible, 9-Fr balloon perfusion catheters are placed in the renal arteries to infuse with cold perfusate
via a standalone circuit (Fig.8). If LHB was used, the celiac trunk and SMA are
perfused with isothermic blood at 400–500 mL/min from a modied circuit.
Endarterectomy of branching arteries is performed as needed. When dissection
extends into the origins of the visceral vessels, the septum is excised or fenestrated,
or the false lumen is sutured closed or obliterated by placing a balloon-expandable
Management of Chronic Dissection of the Descending Thoracic and Thoracoabdominal…
https://t.me/med1917
Fig. 8 Initiation of visceral perfusion and the intercostal patch anastomosis. (Inset) Isothermic
blood is used to perfuse the celiac axis and the superior mesenteric artery (SMA); cold solution is
used to perfuse the renal arteries. Used with permission of Baylor College of Medicine
435
stent (7×15mm) inside the true lumen. These stents are positioned and expanded
within the affected branch under direct vision and without guidewires, as detailed
elsewhere [33].
If distal aortic repair ends at the level of the renal and visceral vessels (i.e., an
extent I TAAA repair), the distal end of the graft can be tailored in a beveled fashion
and sutured end-to-end with 3–0 polypropylene suture; distal fenestration is performed to ensure that both lumens remain perfused. Otherwise, repair necessitates
reimplanting visceral arteries by using an island patch, bypass grafts, or both.
Although a single patch can be used to reimplant all 4 visceral arteries, more commonly, the celiac, superior mesenteric and right renal arteries are reimplanted
together as a 3-vessel patch to an opening made in the side of the graft. The remaining left renal artery is subsequently addressed and continues to undergo cold renal
perfusion. Once the celiac, superior mesenteric, and right renal arteries are reimplanted, the cross-clamp is moved distally to a position below the visceral patch,
thereby restoring perfusion to these arteries.
Single or multiple bypass grafts (including a prefabricated 4-branched graft) are
used more frequently in repairs of chronic dissection than in repairs of aneurysm
because of a tendency toward displacement of visceral artery origins and in efforts
to minimize the residual aortic tissue associated with MFS.The 4-branched graft
436
https://t.me/med1917
Fig. 9 The distal anastomosis is performed, which, when a branched graft is used, is typically
performed before the visceral arteries are reattached. Visceral perfusion is continued. Used with
permission of Baylor College of Medicine
C. Köksoy et al.
technique affords a durable repair in patients with heritable thoracic aortic disease
by eliminating residual native aorta in the visceral segment, thereby preventing the
future development of patch aneurysm; additionally, anastomotic tension is reduced
in this approach, which decreases the likelihood of late pseudoaneurysm formation.
Because of the extended lower-extremity ischemic time necessitated by completing
4 separate anastomoses, the distal aortic anastomosis is performed before the visceral arteries are attached to the graft, enabling distal perfusion (Fig.9). Meanwhile,
visceral arteries are separately perfused. The order of visceral artery anastomosis
usually is the right renal artery, the SMA, the celiac trunk, and the left renal artery
as detailed elsewhere [34] (Fig.10). Additional adjustments for repair in patients
with MFS include using a ner suture (e.g., 4–0 instead of 3–0 polypropylene
suture) and directly incorporating sutures into the visceral artery rather than merely
approaching the ostia [34].
Distal Anastomosis
The distal aortic anastomosis usually is constructed at the level of the aortic bifurcation (or, occasionally, to each iliac or femoral artery separately). If the chronic
dissection continues distally, the septum is fenestrated by resecting wedges of the
dissecting membrane proximally and distally from within the aortic cuffs,
Management of Chronic Dissection of the Descending Thoracic and Thoracoabdominal…
https://t.me/med1917
437
Fig. 10 Right renal artery anastomosis with a branched aortic graft, created after the distal aortic
anastomosis was completed. (Inset) Superior mesenteric artery anastomosis to the branched aortic
graft. Used with permission of Baylor College of Medicine
allowing blood to ow through both true and false channels after the reconstruction is completed. As needed, a bifurcated graft is anastomosed to the junction of
the internal and external iliac arteries or more distally. The distal end of the aortic
graft is trimmed to the appropriate length, and the distal anastomosis is performed
end-to- end with continuous 3–0 or 4–0 polypropylene suture (depending on the
quality of the tissue). The circumference of the distal anastomosis is selectively
reinforced with pledgeted 3–0 polypropylene sutures in an interrupted mattress
fashion. Then the patient is placed in Trendelenburg position, a 27-gauge needle
is used to puncture multiple de-airing holes in the graft, and the aortic cross-clamp
is slowly removed to re-establish blood ow to the pelvis and both lower
extremities.
If the left renal artery is still receiving perfusate, it is now mobilized. A sidebiting clamp is placed on the aortic graft, and ame cautery is used to make a 1-cm
hole in the Dacron. The balloon perfusion catheter is removed, and an end-to-side
anastomosis is completed with a 5–0 polypropylene suture and reinforced as need
with pledgeted mattress suture. If the artery is of inadequate length, a small- diameter
(8-mm) graft is used to bridge the distance. Before the suture is tied down, the
438
https://t.me/med1917
side- biting clamp is released to deair the aorta through the nal anastomosis. At this
time, the inferior pulmonary vein is decannulated, and the purse-string suture is
tied down.
C. Köksoy et al.
Hemostasis andClosure
All anastomoses and suture ligatures are checked for bleeding and are reinforced as
needed. After protamine has been given and surgical hemostasis has been secured,
blood products are transfused as necessary to reverse any coagulopathy. The cut
edges of the opened native aorta are cauterized. The completed repair is inspected
to make sure that the main graft and its branches lie properly without kinking
(Fig.11). Both femoral arteries, both left renal arteries, the proper hepatic artery,
and intestinal arterial branches are palpated for pulses and to ensure adequate blood
ow. The kidneys are palpated for turgor, the bowel is visualized to conrm that it
is well perfused, and the spleen is inspected for injury. A closed-suction abdominal
drain is placed in the upper left retroperitoneal space. The left hemidiaphragm is
reapproximated up to the costal margin with a continuous 1–0 polypropylene suture.
Two straight 36-Fr chest tubes are placed in an anteroapical and posterobasal position within the left chest cavity. The abdominal fascia and chest are closed.
Postoperative Care
Distal aortic dissection repair is a tremendous undertaking, requiring supportive
care in the postoperative period. The patients are kept intubated overnight to control
parameters and achieve optimal outcomes. Standard intensive care monitoring and
volume resuscitation are essential; in addition, the patients’ neurological status is
veried every hour. The CSF pressure should be 15–20mmHg. To achieve this goal,
the CSF can be drained up to 10mL/h, with a maximum quantity of 25mL/4h.
Exceeding this amount can lead to intracranial hemorrhage or herniation. In the
event of emerging spinal cord decit, the target CSF pressure is lowered to
10mmHg, the goal mean arterial pressure (MAP) is increased to 90–110 mmHg,
and the target hemoglobin level is raised to >10g/dL.The patient is administered
intravenous mannitol (12.5 g/L) and dexamethasone (10 mg/L) every 12 h for
24–48h. If the CSF drain was removed before the onset of paraparesis or paraplegia, it should be quickly reinserted. In the absence of spinal cord complications, the
CSF drain can be removed between 24–48h postoperatively. Before removal, the
drain can be clamped for 12–24h to ensure the absence of neurological sequalae.
Patients can be extubated the morning after surgery when they are alert, oriented,
and capable of protecting their airway. Typically, on postoperative day 4, the patient
Соседние файлы в папке Библиотека им академика М.И. Перельмана